Actinic keratosis (AK) is a form of dysplastic epidermal lesions resulting from chronic and excessive UV exposure with a certain risk to become cancerous. The use of sunscreens to prevent photodamages is advocated by the current guidelines on AK treatment. To be efficient a photoprotection has to involve UV filters but also secondary factors such as antioxidants and anti-inflammatory agents able to counteract the photochemical and genetic cascade triggered by UVs. In the present work we used an in vitro model of human skin (Phenion® Ft) in order to assess the photoprotective potential of a sunscreen containing inorganic sun-filters (50+ SPF) and 0.1% octatrienoic acid (KERA’+) after UVA (10J/cm2) and UVB (25mJ/cm2) by mean of evaluation of the number of sunburn cells and apoptotic keratinocytes. We also investigated the alterations in the gene expression of marker involved in apoptosis (TP53), inflammation/immunosuppression (interleukin 6 and interleukin 8), oxidative stress (oxidative stress response enzyme heme oxygenase 1), remodeling (metalloproteinase 1) and cell-cell adhesion (E-cadherin) was investigated. Gene expression was investigated using quantitative real-time PCR. A sunscreen with only inorganic sun-filters (50+ SPF) was used as positive control. Obtained results demonstrated that the two studied sunscreen preparations (with and w/o 0.1% octatrienoic acid, respectively) can be distinguished about their ability to prevent UVs-induced damages. Synergism between the inorganic filters and 0.1% octatrienoic acid was found (KERA’+) on all the endpoints analyzed and this effect was found significant (p<0.05). Our data revealed that topical application of a sunscreen containing inorganic filters (50+ SPF) and 0.1% octatrienoic acid can protect from SBC formation, reduce the number of apoptotic keratinocytes and protect from the main molecular alterations caused by UVs radiations.

ESDR291 - In vitro efficacy of a sunscreen (50+) and octatrienoic acid 0.1% in actinic keratosis and UVs damages

50th Annual Meeting of the European Society for Dermatological Research. VIRTUAL MEETING